In the accompanying drawings:
FIG. 1a illustrates a rear view of a vehicle prior to the initiation of a roll event;
FIG. 1b illustrates a rear view of a vehicle during a roll event;
FIG. 2 illustrates a block diagram of a rollover detection system;
FIG. 3 illustrates a flow diagram of a rollover detection algorithm;
FIG. 4 illustrates a flow diagram of a data acquisition and preprocessing algorithm incorporated in the rollover detection algorithm;
FIG. 5 illustrates a flow diagram of a safing algorithm incorporated in the rollover detection algorithm;
FIG. 6 illustrates a flow diagram of the rollover detection algorithm;
FIG. 7 illustrates a flow diagram of an algorithm incorporated in the rollover detection algorithm for determining if sensor recalibration is required;
FIGS. 8a, 8b and 8c are tables that illustrate details of the rollover detection algorithm;
FIGS. 9a and 9b are tables that illustrate examples of values of parameters of the rollover detection algorithm;
FIG. 10 illustrates a table of conditions associated with various rollover events and non-rollover events;
FIG. 11a illustrates a plot of filtered roll rate, roll angle and filtered lateral acceleration of a vehicle subjected to a corkscrew roll test designated as Test A, resulting in a rollover event;
FIG. 11b illustrates a plot of filtered roll rate, roll angle and filtered lateral acceleration of a vehicle subjected to a corkscrew roll test designated as Test B, resulting in a non-rollover event;
FIG. 11c illustrates a plot of filtered roll rate, roll angle and filtered lateral acceleration of a vehicle subjected to a deceleration sled test designated as Test C, resulting in a non-rollover event;
FIG. 11d illustrates a plot of filtered roll rate, roll angle and filtered lateral acceleration of a vehicle subjected to a deceleration sled test designated as Test D, resulting in a rollover event;
FIG. 12 illustrates plots of a figure-of-merit and an associated deployment threshold for a rollover measure as a function of time, in accordance with a measures algorithm, for the rollover event of Test D and the non-rollover event of Test C;
FIG. 13 illustrates a plot of roll rate as a function of time for a signal having a roll rate offset;
FIG. 14 illustrates plots of roll angle as a function of time based upon the data of FIG. 13, for various associated processes for determining roll angle from roll rate; and
FIG. 15 illustrates plots of roll rate as a function roll angle, and plots of associated rollover thresholds, in accordance with an energy algorithm, for the rollover event of Test A and the non-rollover event of Test B.
There exists a need for a vehicle rollover detection system that provides for discrimination of vehicle rollover sufficiently quickly to enable associated safety restraint actuators, e.g. seat belt pretensioners, air bags or roll curtains, to be deployed before an initial head contact with the interior of the vehicle, particularly for the types of rollovers resulting in relatively fast head closure times. For example, there are some roll events for which head closure may occur before it can be reliably determined from the physics of the roll event whether the vehicle will completely rollover. There further exists a need for a robust vehicle rollover detection system that provides for sufficiently fast discrimination of vehicle rollover responsive to either relatively slow or relatively fast rollover events.